I'm having a bit of trouble with this, and can't get my numbers to come out correctly.
Here's an example: Get a maximum of n items, composed of the following: x burgers y hot dogs z fruit w napkins
where x,y,z are less than n and w is more than n.
How many different combinations can you make from these?
I would assume it would be (n+4-1) C x - (x+4-1) C x - (y+4-1) C y - (z+4-1) C z + (x+y+4-1) C (x+y) + (x+z+4-1) C (x+z) ...
or am I doing something wrong?